Host-parasite coevolution requires additive genetic variation in the relevant host and parasite traits, reciprocal effects on the fitness traits of the two populations, and a dependence of the outcome of the host-parasite interaction on the combinations of genotypes involved.
Analyses of selection on fitness-related traits by reciprocal introductions served as guidelines for the expected pattern of RAPD variation.
Mathematical theory has also indicated that, given the right conditions, divergence is expected to occur readily between competing species by a coevolutionary sequence of reciprocal changes in the traits used to consume resources (Taper and Case 1985; Abrams 1986b; Doebeli 1996).
For example, in the human genome, more than 50%% of the genes have shown preferential expression of the paternal or maternal allele due to various mechanisms [ 69], indicating that our approach may apply to a wide range of complex traits, whenever reciprocal heterozygotes generate different genotypic values.
A generally accepted strategy to study whether a certain candidate gene is involved in a polygenic trait is reciprocal hemizygosity analysis [ 36].
Although our results are indicative of reciprocal adaptations following selection on traits influencing relative fitness, it is not known at present what traits may be involved.
Takai et al. (2014) observed a similar reciprocal effect for yield component traits and photosynthetic rate.
We also analysed the extent to which sex and the direction of the reciprocal cross impacted on the traits of interest.
Thus, it will be possible to determine whether or not QTLs identified in one mapping population likewise influence quantitative traits in the reciprocal mapping population.
The perspective developed here explains why the eukaryotic cell arose just once in 4 billion years of evolution; why there are no surviving evolutionary intermediates between prokaryotes and eukaryotes; why eukaryotes are morphologically complex and share many common traits; and why reciprocal sex arose in eukaryotes but not in prokaryotes.
In the reciprocal cross (T×M), the various traits were not significantly different from those in the control crosses, except that mating duration doubled, with the male having observed difficulty disengaging from the female.
